09.09.13
Nutraceutical: Iron
Indication: Maternal Anemia
Source: British Medical Journal June 2013; 346:f3443
Research: This systematic review and meta-analysis sought to summarize evidence on the associations of maternal anemia and prenatal iron use with maternal hematological and adverse pregnancy outcomes; and to evaluate potential exposure-response relations of dose of iron, duration of use and hemoglobin concentration in prenatal period with pregnancy outcomes. Data sources included searches of PubMed and Embase for studies published up to May 2012 and references of review articles. Randomized trials of prenatal iron use and prospective cohort studies of prenatal anemia were selected; cross sectional and case-control studies were excluded.
Results: Forty-eight randomized trials (17,793 women) and 44 cohort studies (1,851,682 women) were included. Iron use increased maternal mean hemoglobin concentration by 4.59 (95% confidence interval 3.72 to 5.46) g/L compared with controls and significantly reduced the risk of anemia (relative risk 0.50, 0.42 to 0.59), iron deficiency (0.59, 0.46 to 0.79), iron deficiency anemia (0.40, 0.26 to 0.60), and low birth weight (0.81, 0.71 to 0.93). The effect of iron on preterm birth was not significant (relative risk 0.84, 0.68 to 1.03). Analysis of cohort studies showed a significantly higher risk of low birth weight (adjusted odds ratio 1.29, 1.09 to 1.53) and preterm birth (1.21, 1.13 to 1.30) with anemia in the first or second trimester. Exposure-response analysis indicated that for every 10 mg increase in iron dose/day, up to 66 mg/day, the relative risk of maternal anemia was 0.88 (0.84 to 0.92) (P for linear trend<0.001). Birth weight increased by 15.1 (6.0 to 24.2) g (P for linear trend=0.005) and risk of low birth weight decreased by 3% (relative risk 0.97, 0.95 to 0.98) for every 10 mg increase in dose/day (P for linear trend<0.001). Duration of use was not significantly associated with the outcomes after adjustment for dose. Furthermore, for each 1 g/L increase in mean hemoglobin, birth weight increased by 14.0 (6.8 to 21.8) g (P for linear trend=0.002); however, mean hemoglobin was not associated with the risk of low birth weight and preterm birth. No evidence of a significant effect on duration of gestation, small for gestational age births and birth length was noted. Researchers concluded that daily prenatal use of iron substantially improved birth weight in a linear dose-response fashion, probably leading to a reduction in risk of low birth weight. An improvement in prenatal mean hemoglobin concentration linearly increased birth weight.
Indication: Maternal Anemia
Source: British Medical Journal June 2013; 346:f3443
Research: This systematic review and meta-analysis sought to summarize evidence on the associations of maternal anemia and prenatal iron use with maternal hematological and adverse pregnancy outcomes; and to evaluate potential exposure-response relations of dose of iron, duration of use and hemoglobin concentration in prenatal period with pregnancy outcomes. Data sources included searches of PubMed and Embase for studies published up to May 2012 and references of review articles. Randomized trials of prenatal iron use and prospective cohort studies of prenatal anemia were selected; cross sectional and case-control studies were excluded.
Results: Forty-eight randomized trials (17,793 women) and 44 cohort studies (1,851,682 women) were included. Iron use increased maternal mean hemoglobin concentration by 4.59 (95% confidence interval 3.72 to 5.46) g/L compared with controls and significantly reduced the risk of anemia (relative risk 0.50, 0.42 to 0.59), iron deficiency (0.59, 0.46 to 0.79), iron deficiency anemia (0.40, 0.26 to 0.60), and low birth weight (0.81, 0.71 to 0.93). The effect of iron on preterm birth was not significant (relative risk 0.84, 0.68 to 1.03). Analysis of cohort studies showed a significantly higher risk of low birth weight (adjusted odds ratio 1.29, 1.09 to 1.53) and preterm birth (1.21, 1.13 to 1.30) with anemia in the first or second trimester. Exposure-response analysis indicated that for every 10 mg increase in iron dose/day, up to 66 mg/day, the relative risk of maternal anemia was 0.88 (0.84 to 0.92) (P for linear trend<0.001). Birth weight increased by 15.1 (6.0 to 24.2) g (P for linear trend=0.005) and risk of low birth weight decreased by 3% (relative risk 0.97, 0.95 to 0.98) for every 10 mg increase in dose/day (P for linear trend<0.001). Duration of use was not significantly associated with the outcomes after adjustment for dose. Furthermore, for each 1 g/L increase in mean hemoglobin, birth weight increased by 14.0 (6.8 to 21.8) g (P for linear trend=0.002); however, mean hemoglobin was not associated with the risk of low birth weight and preterm birth. No evidence of a significant effect on duration of gestation, small for gestational age births and birth length was noted. Researchers concluded that daily prenatal use of iron substantially improved birth weight in a linear dose-response fashion, probably leading to a reduction in risk of low birth weight. An improvement in prenatal mean hemoglobin concentration linearly increased birth weight.